This　paper　aims　to　offer　a　lightweight　design　method　of　the　missile　engine　support　structure　based　on　the　topology　optimization　by　taking　advantage　of　the　computer　numerical　simulation　and　3D　printing　technology.　Taking　use　of　3D　printing　in　the　shape　of　heterogeneous　structures　and　personalized　manufacturing　advantages,　a　design　process　is　proposed　including　a　computer　modeling,　numerical　simulation,　3D　printing　and　engineering　verification　of　the　missile　engine　lightweight　structure.　Based　on　the　finite　element　method,　a　topology　optimization　algorithm　based　on　the　minimum　potential　energy　of　structure　is　proposed.　The　design　methodology　has　the　following　aspects:　first,　the　design　object　needs　to　complete　three-dimensional　modeling　by　a　computer　aided　design　(CAD)　software　(UG);　then,　the　topology　optimization　model　was　established　by　a　computer　aided　analysis　(CAE)　software　(HyperWorks);　finally,　the　topology　optimization　results　are　fed　back　into　the　design　for　the　final　lightweight　design　model　and　3D　printing.　In　terms　of　analytical　verification,　the　stress　and　displacement　results　of　the　topology　optimization　model　are　examined　by　numerical　simulation;　this　paper　uses　HyperWorks　for　thermodynamic　numerical　simulation;　the　maximum　bearing　capacity　of　the　structure　is　analyzed　by　engineering　test.　The　experimental　results　show　that　this　study　can　achieve　the　purpose　of　lightweight　in　the　case　of　certain　constraints,　while　weight　loss　effect　can　reach　11.06%.　In　addition,　3D　printing　technology　combined　with　numerical　simulation　can　shorten　the　development　cycle　and　improve　the　design　efficiency.